.QQ whitman: [Vol. IV. 



eludes that in copulation the two individuals lie back to back, 

 and that the terminal portions of the genital sacs of the male are 

 everted and inserted as penes in the corresponding non-everted 

 parts of the female. 



The spermatozoa, originating like the ova in a so-called " geni- 

 tal plate," fall into the body-cavity in an imperfectly developed 

 state ; after attaining maturity, they collect in the genital sacs, 

 and are there united into bundles or spermatophores [p. 793]. 

 In this form they may pass, during the act of copulation, into 

 the genital sacs of the female, thence into her body-cavity, 

 where they meet and penetrate the ova. Fecundation is thus 

 accomplished before oviposition. 



Although Dr. Eisig does not seem to have witnessed the act 

 of copulation, his statements rest on many concurrent evidences. 



The most remarkable feature of this copulation remains to be 

 mentioned. Dr. Eisig reports [pp. 791-92] that the ripe males 

 copulate not only with adult females, but also with unripe fe- 

 males, and even with juvenes in which the sex has not yet 

 become manifest ; and what is still more astounding, with young 

 individuals of their ozvn sex. The proof of this lies in the fact 

 that the genital sacs of young males were found stuffed with 

 spermatophores before their genital plates had come into func- 

 tional activity. They must therefore have received their sper- 

 matozoa from without. 



These facts prove that the male is capable of discharging his 

 function effectively without the aid of any co-operative act on 

 the part of the female, and in this respect the copulation bears 

 some resemblance to that of Clepsine. But there seems to be 

 no evidence of spermatophores attached to the exterior, 



6. ArtJiropods. 



The spermatophores of Etipagiirus were seen by Swammerdam 

 {Bibel der Nature, p. 87), and described as " lauter regelmas- 

 sigen Theilchen." Whether they represented eggs or spermato- 

 zoa was left undecided. About a century later, in 1841-42, the 

 decapod spermatophores were rediscovered by Kolliker, and 

 their purpose and origin made known through his observations 

 and those of Von Siebold {cf. Miil. Arch., 1842, pp. cxxxv-vi). 

 It seems probable, from Grobben's observations (Claus's Arbeiten, 

 I, 188 1, p. 67), that all decapods produce spermatophores. The 



